Conventional devices and methods for measuring, for example a room for remodeling, are slow, labor intensive and not very accurate. Usually, two persons take measurements with tape measure and protractors.
The most modern methods use laser measuring devices. These devices are extremely expensive and have limited accuracy on many surfaces. Their accuracy is especially diminished where accuracy is most desired, such as in corners and on curved surfaces.
Several devices measure a three-dimensional object by placing a probe on multiple points on the object and determining the relative positions of the points from their positions relative to the probe's base unit.
For example, U.S. Pat. No. 4,703,443 of Maiyasu titled Device for Measuring the Shape of a Three-Dimensional Object describes using a probe on the end of an arm comprised of a plurality of arm members. The relative location of a probed point is determined from the angles of the arm members.
The device of U.S. Pat. No. 6,785,973 of Janssen titled Measuring Device Comprising a Movable Measuring Probe uses a tethered probe coupled to a ball joint. The relative location of a probed point is determined by measuring the length of the tether and the rotation of the ball joint.